Ftir line width analysis in hydrogen bond liquid crystals

• Thermotropic liquid crystals homologues series comprising of four homologues are synthesized. Non-cyclic complementary hydrogen-bond leads to enhance device savvy Nematic phase and 3D tilted Smectic G phases. • For the first time in the history of thermotropic liquid crystals, the FTIR line width analysis has been undertaken for these materials to understand the influence of alkyloxy carbon number. • An overview of the observed skewed nature reveals an overall negative nature as to infer a monotonical steep decent behaviour on higher wave number side as observed in non-cyclic structured complementary hydrogen-bond liquid crystalss. Series of sparingly reported non-cyclic liquid crystals (LC) formed by complementary type of hydrogen bonding (HB) interaction, viz., BA+nOBAs are synthesized from dissimilar mesogenic components using benzoic acid BA and alkyloxy benzoic acids nOBAs for n equal to 9, 10, 11 and 12. Abundance of Nematic and SmG LC phases are characterized by polarized optical microscopy and differential scanning calorimetry techniques. Complementary HB interaction is confirmed by FTIR technique as manifested through relevant bathochromic or hypsochromic shift. Linear hydrogen-bonding (HB) by soft covalent interaction with infinite rotational degrees of freedom about long molecular axis is further constrained in the present complementary type of HBLCs. Large length of flexible end chain influences nematic phase stability as mediated by odd-even effect and axial polarizabilities. Growth of LC phase orientation fluctuations, configuration of complementary HB, its non-cyclic structure, chemical moieties, and end chain length etc., are studied for director alignment. For the first time, the FTIR line width analysis is carried out in the direction of stability for LC phases. Hydroxyl stretching rarely resolved by two IR absorptions, apart by 72 to 75 cm -1 is attributed to its non-cyclic HBLC structure. Non-cyclic HB is inferred to defend the fast dynamics (+ve skewed, at a maximum ∼1.18) around carbonyl moiety to promote relatively spontaneous nematic orientational order. In comparison with cyclic HBLC nOBAs, an increase of device savvy nematic LC phase stability (to maximum of 50 °C) and its depressed up to ∼70 °C) abundance towards ambient temperatures are observed in the non-cyclic HBLCs.